Touch sensing devices allow a user to conveniently and directly interface with electronic systems and displays in an intuitive manner. For example, a user can carry out a complicated sequence of instructions by simply touching an on-display touch screen at a location identified by an icon. While the user physically interacts with the sensor portion of the touch system, controller electronics operate behind the scene to perform calculations based on received touch signals so that information such as touch position may be determined. The sensor portion and the controller electronics portion are designed to function together such that the signals generated by the sensor portion in response to a touch input may be used by the controller electronics to determine valid touch positions. Because the sensor and controller are designed to function together, replacing the sensor portion (for repair, upgrading, or other reasons) may require replacing the controller or manually uploading new firmware onto the controller.